air valve selection help

This website seemed like a good place to ask so here I am. I have no idea of terminology and so forth so I'm hoping I can describe what I need and someone can tell me what it's called so I can stop off at Lowe's and grab it.

What I'm looking for is a simple, cheap valve that will easily allow air through in one direction but will stop it travelling in the opposite direction without my having to turn a lever (like you would with a ball valve). Can anyone tell me what I need please?

There are many types of check valves, choosing the proper one depends on your application. If you use the bronze 'flapper' type commonly found in the plumbing department, it'll leak a small amount of air. It's designed for water, not air. If a small leak-back is OK, this is about as cheap as you can get.

If it's on the discharge of a compressor, the valve will need to deal with considerable heat. Up to 400 degrees. 'In-tank' compressor valves are made for this purpose. Most of these have a tap to go to the pressure switch unloader valve.

If it needs to be leak tight, get something with a fluoropolymer disc, or an O ring seal.

Some of the plumbers around here know more than I do about check valves, you might have better luck in the plumbing forum.

All I really need it to do is stop air from flowing in one direction and to easily (low PSI) allow air to flow in the other direction. If anyone has any idea of a specific check valve that can do that, I'd appreciate knowing about it.

I don't mean to be overly picky here, there's just so many different types to choose from.

What type of application? What is the flow rate? How much pressure drop can be tolerated across the valve? How much leak-back is acceptable? What is the maximum pressure in the system? What is the maximum pressure the valve will need to block?

I realize that's a lot of questions, and approximate answers are OK, but the wrong type of valve can be a major irritation.

Rob

P.S. I'm not an engineer, I've just got some experience with valves, and have learned from my mistakes.